Air migration into landfill gas collection systems is the number one issue that prevents more than 75% of all landfills from being candidates for beneficial use renewable fuels projects. Enhancing landfill gas quality for beneficial use as a renewable fuel or renewable natural gas (RNG) allows the landfill owner to receive enhanced revenue for their gas and reduces carbon dioxide (CO2), nitrogen oxide (NOx), and sulfur oxide (SOx) created by the unnecessary oxidation of the landfill gas by a landfill flare.
Landfill gas combustion engines for electric generation are limited to the percentage of oxygen in the fuel they burn. High oxygen (O2) results in engines failing and high repair costs. Landfill gas engines are more sensitive to O2 ingress from the gas collection system than flares such that engines may be programmed to shut down if O2 exceeds 2%. Proactive operators of the landfill gas collection systems are therefore required to minimize O2 within the incoming landfill gas. Typically, when landfill methane concentrations are reduced, the air intake flow rate (oxygen) to the engine increases and combustion temperatures rise. Landfill gas's oxygen concentration during the combustion process could vary having the potential to impact emissions and if engine's control system does not have the automatically adjustments the landfill engine could be in violation of the landfill's air permit.
Existing landfill gas upgrade technologies refine landfill gas to meet pipeline quality and compressed natural gas (CNG), but are limited by the amount of air that is contained in the raw landfill gas. This limitation comes in three forms 1) increased equipment capital cost to treat excess air (oxygen and nitrogen), 2) existing technology operating cost, and 3) safety limits on the amount of oxygen a system can handle.
High oxygen concentrations in landfill gas possess a safety problem dealing with all the usages of landfill gas; even flaring the landfill gas has its limitations.
The process of flaring, burning or engine combusting converts hydrogen Sulfide (H2S) to SOx. All landfills produce H2S gas with concentrations from 50 ppm to 2000 ppm or more. All of the landfill gas technologies usages have their limitations in handling the H2S concentration that they can process. Even flaring high (>500 ppm) concentrations of H2S is limited in populated areas in the world which mandate a pre-flare H2S process treatment system. There is a great need to control and manage the amount of H2S that is being pulled from a landfill to reduce costs of H2S treatment and reduce SOx emissions. Prior Art teaches no effective system and method to solve the problem to manage the concentration of H2S inside of a landfill.
It is an object of this invention to provide a system and method for onsite controlled analytical testing, well head tuning and technician training to quickly improve the quality of the landfill gas in regard to the reduction of air in the total landfill gas flow. It is a further object of the present invention to map out concentrations of H2S areas of landfills; allowing for efficient evaluation and selective reduction of H2S. Another object of the present invention is to evaluate landfills for potential renewable gas projects to confirm actual landfill gas flow, gas quality and existing landfill gas contaminates.